Splitwise MCP

A Model Context Protocol server that connects Claude to Splitwise, giving you natural-language access to your expenses, groups, friends, and balances.

[!WARNING] AI-developed project. This codebase was entirely built and is actively maintained by Claude Code. No human has audited the implementation. Review all code and tool permissions before use.

What you can do

Ask Claude things like:

• "What do I owe?"
• "Add a $50 dinner expense to the vacation group"
• "Split this hotel bill 60/40 with Sarah"
• "Who's in the trip group?"
• "Add Meredith to the household group"
• "Show me recent expenses"
• "Delete that duplicate expense"

Requirements

• Claude Desktop or Claude Code
• Node.js 20.6 or later
• A Splitwise account and API key

Installation

Option A -- npx (recommended)

npx -y splitwise-mcp

Add to your Claude config (.mcp.json or Claude Desktop config):

{
  "mcpServers": {
    "splitwise": {
      "command": "npx",
      "args": ["-y", "splitwise-mcp"],
      "env": {
        "SPLITWISE_API_KEY": "your-api-key-here"
      }
    }
  }
}

Option B -- from source

git clone https://github.com/chrischall/splitwise-mcp.git
cd splitwise-mcp
npm install
npm run build

Add to Claude Desktop config:

• Mac: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "splitwise": {
      "command": "node",
      "args": ["/absolute/path/to/splitwise-mcp/dist/index.js"],
      "env": {
        "SPLITWISE_API_KEY": "your-api-key-here"
      }
    }
  }
}

Getting your API key

1. Go to secure.splitwise.com/apps/register
2. Register an app (name and description can be anything)
3. Copy the API key from the app detail page

Credentials

Env var	Required	Notes
SPLITWISE_API_KEY	Yes	API key from splitwise.com/apps/register

Available tools

20 tools across 5 domains. All tools are prefixed sw_.

User

Tool	What it does
sw_get_current_user	Get the authenticated user's profile
sw_get_user	Get another user's profile by ID

Groups

Tool	What it does
sw_list_groups	List all groups with members
sw_get_group	Group details including members and balances
sw_create_group	Create a new group
sw_delete_group	Soft-delete a group
sw_undelete_group	Restore a deleted group
sw_add_user_to_group	Add a user to a group
sw_remove_user_from_group	Remove a user from a group

Friends

Tool	What it does
sw_list_friends	List all friends
sw_create_friend	Add a friend by email
sw_delete_friend	Remove a friendship

Expenses

Tool	What it does
sw_list_expenses	List or search expenses with filters
sw_get_expense	Full details of a single expense
sw_create_expense	Create an expense (equal or custom split)
sw_update_expense	Edit an existing expense
sw_delete_expense	Soft-delete an expense
sw_undelete_expense	Restore a deleted expense
sw_get_comments	Get comments on an expense
sw_create_comment	Add a comment to an expense
sw_delete_comment	Delete a comment

Utilities

Tool	What it does
sw_get_notifications	Recent activity feed
sw_get_categories	Expense category list
sw_get_currencies	Supported currency codes

Troubleshooting

"SPLITWISE_API_KEY is required" -- set the environment variable in your MCP config or a .env file.

429 rate limit -- Splitwise has undocumented rate limits. Wait a moment and retry.

Tools not appearing in Claude -- go to Claude Desktop > Settings > Developer to see connected servers. Make sure you fully quit and relaunched after editing the config.

Development

npm test        # run the test suite (vitest)
npm run build   # compile TypeScript -> dist/

Project structure

src/
  client.ts         Splitwise API client (auth, request handling)
  index.ts          MCP server entry point
  tools/
    user.ts         sw_get_current_user, sw_get_user
    groups.ts       group CRUD and membership
    friends.ts      friend list and management
    expenses.ts     expense CRUD, comments
    utilities.ts    notifications, categories, currencies

License

MIT